SCITUATE — The doors to Gleaner Gardens, a private garden that features hundreds of varieties of currently flowering rhododendrons, will be thrown open free to the public for the three-day weekend.

The garden dates to the 1950s, when the late George E. Howarth, a landscape artist who was credited with developing some of the state’s most popular parks, began collecting varieties of rhododendrons on his world travels, according to Cynthia Gianfrancesco and Chuck Horbert, who now tend the botanical outpost at 299 Gleaner Chapel Rd. in the village of North Scituate. The premises will be open from 10 a.m. to 4 p.m. each day.

The couple’s efforts to restore the garden after it fell into neglect upon Howarth’s death 20 years ago were rewarded this month when the magazine Traditional Homes published a four-page article with several color photos.

The new owners both work for the state Department of Environmental Management, but in fields unrelated to the cultivation of rhododendrons. In fact, said Gianfrancesco, their connection with the flowering shrub mecca was serendipitous.

“Shortly after we were married eight years ago, we found this house,” Gianfrancesco said yesterday. “We went to look at it, and we didn’t know the garden was there. We started walking through and realized it was all rhododendrons, and that there was quite a collection. We sat down and said, ‘Is this something we are willing to take on?’ because it was a pretty long commitment for a restoration project.”

Howarth had tagged all of the shrubs, but many of the tags had become lost over the years and his records were destroyed accidentally. The couple is still trying to pin down identifications.

“There are over 1,000 varieties in the world,” Gianfrancesco said, “and we have 300 to 400 shrubs with 100 varieties. This is a full-time job.”

She said that last year more than 200 people showed up to walk through the premises during the Memorial Day weekend.

Gianfrancesco is a master gardener and a member of the Gentian Garden Club and the Rhode Island Wild Plant Society.

Only about half the property is occupied by rhododendrons. The rest is woodland and field, and contains azaleas and perennials.

Although there is no fee to visit the garden, Gianfrancesco said that contributions to the Rhode Island Wild Plant Society would be welcomed.

Howarth, who worked 32 years for the state, was superintendent of state parks from 1980 to 1984, when he retired. He was influential in developing Fort Adams State Park in Newport and Fishermen’s Memorial Campground in Narragansett. He also helped design the golf course at Goddard Memorial State Park in Warwick. He was a licensed arborist and served as Scituate’s tree warden.

tmorgan@projo.com